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爆破振动灾害严重威胁着爆破振动场内既有构筑物的安全及稳定。然而,由于毫秒延时爆破的振动载荷表征复杂,若采用简化的三角形或者梯形动力载荷进行分析,与实际的工程情况差异显著。基于对爆破孔内爆破压力变化、炮孔体积扩张、围岩裂隙发展、爆破气体运动等的分析,建立起爆破动力载荷随时间变化的精确数学模型;在远场爆破振动分析时,统一理论下各个爆破孔的动力载荷,其规律满足圣维南定理,因此,可将每分段内各孔的爆破载荷等效为其作用区域上的均布载荷,毫秒延时爆破问题就转化为一个等效边界问题;最后通过有限元数值模拟软件FLAC3D建立三维隧道模型,代入物理力学参数、传播及衰减规律参数以及动力载荷模型,预测峰值速度曲线,与现场实际监测数据进行对比分析,确定数值模拟的准确性,并结合预测的有效应力曲线计算得出爆破安全判据公式。
Blasting Vibration Disasters seriously threaten the safety and stability of the existing structures in the blasting vibration field. However, due to the complicated characterization of the vibration load of millisecond delay blasting, if the analysis is carried out with simplified triangular or trapezoidal dynamic load, the actual engineering situation is significantly different. Based on the analysis of blasting pressure in blasting hole, the expansion of blasting hole, the development of fractures in surrounding rock and blasting gas, an accurate mathematic model of blasting dynamic load changing with time was established. In the analysis of far-field blasting vibration, under unified theory The dynamic load of each blasthole satisfies the Saint-Venant theorem. Therefore, the blast load of each hole in each section can be equivalent to the uniform load on the area of its action. The problem of millisecond delay blasting is transformed into one Finally, through the finite element numerical simulation software FLAC3D, a three-dimensional tunnel model is built and the parameters of physical mechanics, propagation and attenuation and dynamic load model are taken into account. The peak velocity curve is predicted and compared with the actual monitoring data to determine the numerical simulation Accuracy, combined with the predicted effective stress curve calculated blasting safety criteria formula.